package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Autowired
    private IUserService userService;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Override
    public Result queryBlogById(Long id) {
        Blog blog = getById(id);
        if (blog==null){
            return Result.fail("博客不存在");
        }
        queryBlogUser(blog);
        // 查询blog是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        if (user == null){
            // 用户未登录，无需查询
            return;
        }
        Long userId = user.getId();
        String key = BLOG_LIKED_KEY + blog.getId();
        // 判断当前用户是否对该博客点过赞
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    @Override
    public Result queryHotBlog(Integer current) {
        log.info("current:{}", current);
        // 根据用户查询
        Page<Blog> page = this.query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });

        return Result.ok(records);
    }

    @Override
    public Result likeBolg(Long id) {
        // 获取登录用户
        Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + id;
        // 判断当前用户是否对该博客点过赞
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        // 如果未点赞，可以点赞
        if (score == null){
            // 可以点赞，修改数据库， 修改redis
            LambdaUpdateWrapper<Blog> blogLambdaUpdateWrapper = new LambdaUpdateWrapper<>();
            blogLambdaUpdateWrapper.eq(Blog::getId, id).setSql("liked = liked + 1");
            boolean isSuccess = update(blogLambdaUpdateWrapper);
            if (isSuccess){
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }
        }else {
            // 可以点赞，修改数据库， 修改redis
            LambdaUpdateWrapper<Blog> blogLambdaUpdateWrapper = new LambdaUpdateWrapper<>();
            blogLambdaUpdateWrapper.eq(Blog::getId, id).setSql("liked = liked - 1");
            boolean isSuccess = update(blogLambdaUpdateWrapper);
            if (isSuccess){
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        // 查询top的点赞用户 zrange key 0 4
        String key = BLOG_LIKED_KEY + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        // 解析出用户id
        if (top5==null||top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        // 根据用户id查询用户，返回
        String str = StrUtil.join(",", ids);
        List<User> users = userService.query().in("id", ids).last("ORDER BY FIELD(id,"+str+")").list();
        List<UserDTO> userDTOS = users.stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class)).collect(Collectors.toList());
        return Result.ok(userDTOS);
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 1. 找到收件箱
        Long userId = UserHolder.getUser().getId();
        // 2. 查询收件箱
        String key = FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet().
                reverseRangeByScoreWithScores(key, 0, max, offset, 3);
        if (typedTuples==null||typedTuples.isEmpty()){
            return Result.ok();
        }
        // 3. 解析数据：blogId, minTime, offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            ids.add(Long.valueOf(typedTuple.getValue())); // blog的id
            Long time = typedTuple.getScore().longValue(); // 得到时间戳
            if (time == minTime){
                os++;
            }
            else {
                minTime = time; // 时间戳
                os = 1;
            }
        }
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        blogs.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setMinTime(minTime);
        scrollResult.setOffset(os);
        return Result.ok(scrollResult);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

}
